Technical information

ManualsBrandsRadio Shack ManualsCalculatorEC-293

Line Printer Output

LEVEL II BASIC

There are two statements for

output

to

the

Line Printer, LPRINT

and

LUST.

See

the

LEVEL II BASIC Reference Manual for details.

Note:

If

you

don't

have a line

printer

connected, LPRINT and

LUST

will cause

your

Computer

to

lock up, requiring

you

to

Reset

it. (Hold down BREAK while

you

press Reset.) Resetting

the

Computer

with

the

Expansion Interface connected will cause

you

to

lose any BASIC program in memory.

Assembly Language

Hex address 37E8

is

memory

mapped

to

the

Line Printer Card-Edge

and serves

as

an

input/output

port.

Before sending a

byte

to

this

port,

check enabled status bits:

PERIPHERALS

bit

7

6

5

4

if

set then status is

...

BUSY

OUT OF PAPER

DEVICE NOT SELECTED

NO FAULT

Note: Check

your

Line Printer Manual

to

see which status bits are

used.

When

the

Printer

is

READY, store

the

byte

(an ASCII code for

the

desired character)

in

hex address 37E8.

For

example,

if

the

ASCII coded character is stored in register C:

SUBROUTINE

TO

OUTPUT

A

BYTE

TO

A

LINE

PRINTER

LOAD

ASCII-CODED

CHARACTER

INTO

C-REGISTER,

THEN

CALL

PRTDVR

PRTDVR

LD

BIT

JP

LD

LD

RET

A,

(37E8H)

7,A

NZ

,PRTDVR

A,C

(37E8H)

,A

CHK

STATUS

BUSY

BIT

SET?

LOOP

WHILE

BUSY

GET

CHARACTER

SEND

IT

TO

LP

RETURN

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